Field of the Invention
The present invention relates to an illumination device of a vehicle, and particularly relates to an illumination device utilizing direct light.
Description of Related Art
Interiors (in some case, exteriors) of vehicles such as automobiles are equipped with illumination structures that provide various use for drivers and/or passengers. In some illumination devices, the light emitted from a light source is utilized as direct light that is directly incident on eyes of a viewer (driver and/or passenger). In the other type of illumination devices, the light emitted from a light source is utilized as indirect light that is reflected by at least one section (illuminated section) of an interior and subsequently incident on the eyes of a viewer. The indirect light has an effect of presenting gentle light while the direct light has an effect of presenting light having high visibility. The indirect light and the direct light are selectively used depending on an object to be irradiated and/or the purpose of illumination.
In some types of illumination devices, light from a light source may be radiated via a light guide. For example, with respect to an illumination device mounted to a door trim of a vehicle and illuminates a handle housing unit that houses an inside handle, Japanese Patent Publication No. 5802103 describes a configuration in which a light guide made of a flexible material is disposed as a light emitter to an outer side (back side) of a decoration panel. Japanese Laid-Open Patent Publication No. 2015-9663 describes a configuration in which a light guide member is positioned between a decoration member and a cover member, and a vehicle cabin is illuminated with light from a linear light-permeable portion formed on a light-permeable decoration member.
Light guide members having a substantially cylindrical shape with a circular cross-section have been used in conventional illumination devices. In the device of Japanese Patent Publication No. 5802103, a light guide member having a substantially circular cross-section is held by a light guide holding member having a reflection surface. With regard to a configuration having a light guide member positioned between a decoration member and a cover member, Japanese Laid-Open Patent Publication No. 2015-9663 describes a configuration having a reflector provided at a surface of the cover member, by which the light which has been reflected toward the outside of the vehicle cabin is reflected to the direction of the interior of the vehicle cabin.
Conventional illumination devices having a light guide member made of a flexible material are each provided with a housing to hold the light guide member. For example, the light guide member is held on a decoration panel using a housing (light guide member holding member) in the device of Japanese Patent Publication No. 5802103. Japanese Laid-Open Patent Publication No. 2015-9663 also describe a configuration in which the light guide member is held by a housing (cover member). However, in a case where light emitted from a flexible light guide member is used as direct light, assembly of a housing disadvantageously increases component cost and man-hours. In addition, an illumination device including a housing has a large size, and therefore is subjected to significant restriction on mounting space.
In a conventional light guide member having a substantially cylindrical shape with a circular cross-section, which is used in an illumination device of a vehicle cabin, light is emitted from the entire circumference of the light guide member. Therefore, in order to enhance illumination efficiency, the light emitted towards the outside must be returned towards the cabin by a reflection layer provided on the housing. In Japanese Patent Publication No. 5802103, a reflection surface is provided on the housing (light guide member holding member) to enhance light utilization efficiency. Also in Japanese Laid-Open Patent Publication No. 2015-9663, a reflection layer is provided on the housing (cover member) to enhance light utilization efficiency. According to the conventional illumination devices using a cylindrical light guide member, it has been difficult to avoid the use of housing due to the requirement to form the reflection layer.
In the conventional illumination devices, in order to prevent illumination of an area other than a target area, a light-permeable member provided with a light-shielding layer is used as a member disposed to the inner side of the vehicle. For example, in the device of Japanese Patent Publication No. 5802103, a light-shielding layer is formed on the lower side of a panel formed of a light-permeable member. Japanese Laid-Open Patent Publication No. 2015-9663 describes a configuration in which a light-shielding layer is formed on the surface of a decoration member made of a light-permeable material, and the interior of the vehicle cabin is illuminated with light from the linear light-permeable section having no light-shielding layer. Thus, in the configuration having a light-permeable member provided with the light-shielding layer, selective options of material used as the decoration member and/or the degree of freedom in design are restricted. Further, the cost for formation of the light-shielding layer increases the total cost.
An object of the present invention is to provide a direct-light illumination device including a light guide member, which is compact in configuration, has a high degree of freedom in mounting design, and has excellent designability.